• The Journal of Korean Academy of Prosthodontics
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• v.62 no.1
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• pp.1-5
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• 2024

Purpose. To investigate the differences in the frequency of post-fitting denture check-ups based on gender, age, insurance status, denture arch, and type among patients aged 65 and above. Methods. This research analyzed 988 patients from National Health Insurance Service Ilsan Hospital's Department of Prosthodontics, who had denture fittings over the last 10 years. Variables including gender, age, insurance status and type, denture arch, and denture type were assessed. Statistical analyses were performed at a 5% significance level. Results. The study incorporated 988 dentures, revealing a median of 3 check-ups post-fitting. Male patients significantly had more visits than females (P = .017), and those with full metal dentures visited significantly more than those with partial dentures (P = .005). Other variables were not significantly influential on the post-fitting check-up frequency. Conclusion. Within this study's confines, an increase in denture adjustment sessions was observed for male patients and those with full metal dentures.

• Journal of the Ergonomics Society of Korea
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• v.30 no.6
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• pp.715-725
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• 2011

Objective: This study is aimed at developing Articulated Human Models(AHM) using superquadrics to improve the geometric accuracy of the body shape. Background: The previous work presents the AHM with geometrical simplification such as ellipsoids to improve analysis efficiency. However, because of the simplicity, their physical properties such as a center of mass and moment of inertia are computed with errors compared to their actual values. Method: This paper introduces a three steps method to present the AHM with superquadrics. First, a 3D whole body scan data are divided into 17 body segments according to body joints. Second, superquadric fitting is employed to minimize the Euclidean distance between body segments and superquadrics. Finally, Fee-Form Deformation is used to improve accuracy over superquadric fitting. Results: Our computational experiment shows that the superquadric models give better accuracy of dynamic analysis than that of ellipsoid ones. Conclusion: We generate the AHM composed of 17 superquadrics and 16 joints using superquadric fitting. Application: The AHM using superquadrics can be used as the base model for dynamics and ergonomics applications with better accuracy because it presents the human motion effectively.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.195-198
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• 2004

One Important problem in a cancer microarray study is to identify a set of genes from which a molecular prognostic indicator can be developed. In parallel with this problem is to validate the chosen set of genes. We develop in this note a K-fold cross validation procedure by combining a 'pre-validation' technique and a bootstrap resampling procedure in the Cox regression . The pre-validation technique predicts the microarray predictor of a case without having seen the true class level of the case. It was suggested by Tibshirani and Efron (2002) to avoid the possible over-fitting in the regression in which a microarray based predictor is employed. The bootstrap resampling procedure for the Cox regression was proposed by Sauerbrei and Schumacher (1992) as a means of overcoming the instability of a stepwise selection procedure. We apply this K-fold cross validation to the microarray data of 92 gastric cancers of which the experiment was conducted at Cancer Metastasis Research Center, Yonsei University. We also share some of our experience on the 'false positive' result due to the information leak.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.5
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• pp.835-844
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• 1997

The purpose of the study was to develop a size chart for elderly women over 60s. In order to investigate the differences in sine and figure, we measured 28 measurements of the 400 samples in Seoul in 1996. The selected measurements were what required to draft a tailored jacket patterns. At the beginning of the study, we surveyed about the difficulties and complaints on clothing of elderly in general with the samples of customers and suppliers for larger sizes. They preferred a jacket when they go out, and most frequently experienced difficulty was not to be able to find a decent clothing of suitable design and fitting size.'chat is why we concentrated the study on the measurements required for jackets. We analyzed the data as follows. 1. As Korean apparel industry use K.S. sizing system, we decided to use the same measurement to categorize the samples, bust and height. 2. We found out the frequency in the sixte chart and suggests the production sixte for over 60s. 3. We suggested some of the distinct figure related characteristics for better fitting.

• Communications for Statistical Applications and Methods
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• v.24 no.4
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• pp.383-396
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• 2017

The model in our approach assumes that computer responses are a realization of a Gaussian processes superimposed on a regression model called a Gaussian process regression model (GPRM). Selecting a subset of variables or building a good reduced model in classical regression is an important process to identify variables influential to responses and for further analysis such as prediction or classification. One reason to select some variables in the prediction aspect is to prevent the over-fitting or under-fitting to data. The same reasoning and approach can be applicable to GPRM. However, only a few works on the variable selection in GPRM were done. In this paper, we propose a new algorithm to build a good prediction model among some GPRMs. It is a post-work of the algorithm that includes the Welch method suggested by previous researchers. The proposed algorithms select some non-zero regression coefficients (${\beta}^{\prime}s$) using forward and backward methods along with the Lasso guided approach. During this process, the fixed were covariance parameters (${\theta}^{\prime}s$) that were pre-selected by the Welch algorithm. We illustrated the superiority of our proposed models over the Welch method and non-selection models using four test functions and one real data example. Future extensions are also discussed.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.11-20
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• 1996

The numerous application of scattered data include the modeling and visualization of physical phenomena. A tetrahedrization is one of pre-processing steps for 4-D surface interpolation. In this paper, various tetrahedrization methods are discussed including, Delaunay, least squares fitting, gradient difference, and jump in normal direction derivatives. This paper discriminates the characteristics of tetrahedrization through visualizing tetrahedral domain. This paper also, provides the tool that can compare and analyze the quality of 4-D space approximation over tetrahedral domain numerically, as well as graphically.

• Journal of Welding and Joining
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• v.14 no.5
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• pp.78-86
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• 1996

Vision sensor was used to track the weld line of the compressor case. The compressor case was fixed in jig equipped with the rotating system, and two torches having one degree of freedom was applied in automatic welding system. The radius of rotation for the compressor case is varying with each rotating angle, while, the angle velocity is constant Therefore, an algorithm to extract the feature of the compressor case for varying rotation angle is needed. To over come the avove difficulties, the curve fitting and composite curve were used. The experiment to verify the proposed algorithm showed desirable results for tracking the welding line of compressor case.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.21 no.2
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• pp.63-73
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• 2017

Segmenting the image into multiple regions is at the core of image processing. Many segmentation formulations of an images with multiple regions have been suggested over the years. We consider segmentation algorithm based on the multi-phase level set method in this work. Proposed method gives the best result upon other methods found in the references. Moreover it can segment images with intensity inhomogeneity and have multiple junction. We extend our method (GLIF) in [T. Dultuya, and M. Kang, Segmentation with shape prior using global and local image fitting energy, J.KSIAM Vol.18, No.3, 225-244, 2014.] using a multiphase level set formulation to segment images with multiple regions and junction. We test our method on different images and compare the method to other existing methods.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.74-77
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• 2006

A scanned Fabry-Perot(F-P) filter and a Multi-Channel Wavelength Locker(MCWL) were used to interrogate fiber Bragg grating sensor array. When the F-P filter scans over the MCWL which works as a multi-reference the temporal peaks profiles correspond to the locking wavelengths. To solve the linearity, stability, and accuracy problems caused by the nonlinear response of F-P filter, a polynomial fitting algerian was used to calculate the relationship between the peak locations and the wavelengths in all the scanning range. Then from the reflected peaks locations and the best fitting line, the Bragg wavelengths can be obtained. The measurement linearity was greatly enhanced with wavelength resolution of about 4 pm in 10Hz scanning frequency.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.3
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• pp.346-359
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• 2012

This study provides basic guidelines to enrich lecture content and teaching methods for university lecturers about basic clothing construction (flat pattern making). The survey was conducted from October $13^{th}$ to December $20^{th}$ 2010 by mail and e-mail on 96 selected clothing departments in Korean universities to investigate the content, method and condition of the course of basic pattern making. A total of 63.3% of survey respondents were PhD graduates, 80 percent majored 'Apparel Science and Technology', average of total teaching experience was 12.84 years and 40 percent had studied abroad. The surveyed universities were 4 year universities (70%), 2-3 year tenure colleges (27%), and Cyber Universities (3%). The average number of students in a class was 28.08 and the lab space and equipment was evaluated positively only when the number of students was 20 or less. The type of measurements for basic pattern drafting were 'individual student's sizes' (62%), 'ready-made clothes sizing system' (25%), 'professor's experiential sizes' (5%), 'dress form sizes' (3%). In addition, the percentage of using 'ready-made clothes sizing system' increased 13% over the previous study (Lee, 2000). At a basic pattern drafting stage, 'the error of body measurements' in the case of using individual student's sizes, 'the poor results of fitting for students who deviate from standard body size' in the case of using ready-made clothes sizing system, 'the lack of education about fitting' in the case of using dress form sizes had been pointed out as shortcomings. A total of 66% of survey respondents carried out muslin fitting; however, a lack of students and teacher feedback about fitting & alteration of paper patterns remained a problem.